Circuit altering device



Oct. 24, 1939. A. HALL 2,177,482

CIRCUIT ALTERING DEVICE Filed Oct. 23, 1954 l-NVENTOR Mal! ATTORNEYS Patented Oct. 24, 1939 PATENT OFFICE 2.177.482. am'snmo nsvror.

Arthur Hall; Endianapolis, ;Ind'., assignor, by mcsne assignments, to 1?. R. Mallory & Co, l no Inpolis, Ind a corporation of Dei= aware Application October .85, 19%, Serial No. 149,5ifi It" 9. ifil. 2M-55 The present invention relates to circuit alterlug devices and, more particularly, to such de vices having a rotating shaft carrying a contact arm adapted to cooperate with means whereby 5 electrical circuits connected to terminals of the device may be altered or resistance interposed therein, for example, volume controls.

General objects of the invention are the provisions of such devices featured by efllcient and l simple means whereby the angle of rotation of the operating shaft may be readily altered in any desired respect and volume controls adapted for simple and ready replacement in sets requiring many different characteristics thereoi.

A more specific object of the invention is the provision of such devices which have a stop adapted to be easily changed ifrom one to another of a plurality of predetermined positions whereby the angle of rotation of the operating shaft so may be limited as desired andsimple structure whereby said step may be so adjusted and fixed. Another object of the invention is the provision of such a volume control which may be mounted with or without a circuit switch com= ll bined therewith, readily adjusted to interpose into circuit diflerent predetermined amounts of fixed resistance, can be mounted in a plurality of positions as the case demands with little alteratlon, and is adaptable to almost any set of condl- W tlons ordinarily encountered in replacement, all

with a minimum of simple adjustments and alterations.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

u The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplifled in the construction hereinafter set forth and the scope of the invention will be indicated in 40 the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in

45 which:

Fig. 1 is a perspective exploded view of the replacement volume control of the present invention;

a Fig. 2 is a perspective view of a cover plate to be used with the device depicted in Fig. 1;

Fig. 3 is a sectional view of the device depicted in Fig. 1 taken substantially on line 23 of Pig. 4; Fig. 4 is a. top plan view of the device depicted in Fig. l with the cover and switch unit removed;

FiFig. 5 is a sectional view taken on line 8-8 c. i

Fig. 6 is an elevational view of the device picted in Fig. l with the removable switch shown in broken lines; and

Fig. 'i is abottom plan view taken on line 5-? of Fig. 3 and with parts broken away.

n Referring to the drawing like numerals refer to like parts throughout. The replacement volume control shown in Figs. 1 to 'i inclusive comprises a base member i3, preferably cup-shaped, sup porting a resistance element consisting oi. a sec tlon i l hereinafter termed "fixed resistance sec tion"'end a second section it hereinafter termed variable resistance section. This resistance element is preferably supported in the cup-shaped base i3 against a suitable insulating liner by means of a wedge ii forced between the tapered ends of the resistance element to cause re sistance element to exert a radial pressure against the side walls of the cup-shaped base. 'I'ermlnale l8 and M are connected to respective ends of the resistance element.

A shaft is rotatably mounted on the base it in any suitable manner preferably as shown in Fig. 3. Upon the shaft is fixedly mounted a core tact arm 21 adapted to ride along the top of the resistance element. The shaft 20 is also provided with an arm 22 fixed thereto and having an end thereof turned substantially at right angles .to form a member 29 disposed adjacent the inner face of the base ii. A portion of thebase is vlded with a lug 29 struck out therefrom adapted to project through the elongated aperture 25. The base I3 is also provided in the preferred form with a plurality of holes 29-29 and the plate 21 is provided with a projecting portion or pin II adapted to seat in any one of the holes "-19 whereby the lug 28 may be positioned in any one of a plurality of positions in the elongated aperture 25. Each hole 29 is indexed along the side wall of the base l3 as is shown in Fig. 6. The plate 21 is secured in any one of the plurality of predetermined positions by means of a nut 3| adapted to engage the collar 26. It is contemplated within the scope of the invention that the A plate 21 is flttedover the collar 28 and pro-' adjustable lug or stop 23 may be mounted upon any suitable member on the outside of or on the inside of the base l3 and that means other than that described may be used between such member and the base l3 to fix the adjustable stop 23 in any one of the plurality of positions. For example, the plurality of holes 23---23 may be formed in the plate 21 and the cooperating projection or pin 30 may be mounted on the base l3.

A circuit terminal 32 is provided with suitable means for making contact with the contact arm 2|.

A cover 33 is mounted upon the base I3. This cover, in the preferred form, is provided with an aperture 34, a slot 35 and holes 38-33 and 31-31.

A toggle switch unit 38 of known construction has an operating arm 39 projecting through a hole in the base plate 40 thereof. The base plate 40 is provided with a resilient tongue 4|, pins 42-42 and lugs 43-43 struck out therefrom. A pin 44 is mounted eccentrically of the shaft 20 on the arm 23. The toggle switch unit 38 is removably mounted on the cover 33 by inserting the tongue 4| in the slot 35 and moving the former laterally relative to the latter until pins 42-42 engage in holes 33, 36 and the lugs 43, 43 engage in the holes 31, 31. The toggle switch arm 39 with the toggle switch unit 33 so mounted projects through the aperture 34 within the path of movement of the pin 44 to be operated thereby.

When the requirements are such as to make undesirable the use of the toggle switch unit 33,

a cover plate 45 is provided having a resilient tongue 4| and struck out lugs 43, 43. This cover plate is adapted to be mounted on the cover 33 in a manner similar to the toggle switch unit 33 to cover the aperture 34.

The shaft 20 of the replacement volume control is shown to be of considerable length and flattened on one side. The shaft is adapted to receive a plurality of types of operating-knobs such as 43, a shim 41 being provided to be used with certain. knobs adapted to be mounted upon shafts having only a small portion of the side thereof removed. The device is supplied to the trade with the elongated shaft so that it may be adapted for mountation under a variety of conditions requiring different lengths of shaft, the person mounting the device having only to cut the shaft to the proper length.

- In many radio sets a certain amount of fixed resistance is required to be connected into the circuit at all times. When none is desired the plate 21 is readily removed whereby the stop 24 allows the contact arm 2| to be rotated to a position where no fixed resistance is included in the circuit. Other circuits require a fixed resistance which may be 100, 200, 300, .400 or 500 ohms. For this purpose the readily adjustable plate 21 is provided so that the person mounting the replacement volume control can seat the projection or pin 30 in the proper indexed hole 23 so that the lug or stop 28 will cooperate with the member 23 to restrict the rotation of the contact arm 2| whereby the desired amount of fixed resistance may be connected in the circuit.

It will thus be seen that the present invention provides circuit altering devices which are feature by readily adjustable means to meet a variety of requirements making unnecessary a large stock of devices each different from the other in construction to meet the many different requirements of different types of radio sets and apparatuses, It is merelynecessary for the repairman to keep in stock a single type of device,

that of the present invention, which can be readily adjusted to meet the particular requirements.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not 'in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific featuresof the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween. I

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a. replacement volume control adapted to replace any one of a plurality of types of volume controls, the combination comprising a base having a projection thereon and an a aperture adjacent thereto, a resistance element mounted thereon comprising a fixed resistance section and a variable resistance section, a rotatable shaft mounted on said base carrying a contact arm engaging said resistance element, a plate mounted adjacent said base, a fixed stop carried by said plate extending through the aperture in said base, means on said shaft to cooperate with said projection and said stop as desired to limit the rotation of said shaft, and index means between said base and said plate to fix the latter relative to the former in one of a plurality of predetermined positions whereby the desired amount of resistance of said fixed resistance section to be permanently connected in circuit may be obtained.

2. In a replacement volume control adapted to replace any one of a plurality of types of volume controls, the combination comprising a base, a resistance element supported thereon, a rotatable shaft mounted on said base carrying a contact arm engaging said resistance element, an adjustable stop adapted to be fixed in a plurality of predetermined positions, means on said shaft to cooperate with said stop to limit the rotation of said shaft, a switch operating member mounted eccentric to said shaft and rotatable therewith, a cover, and a toggle switch mounted on said cover having an operating arm positioned to be engaged by said operating member.

3. In a replacement volume control adapted to replace any one of a plurality of types of volume controls the combination comprising a base, a resistance element supported thereon, a rotatable shaft mounted on said base carrying a contact arm engaging said resistance element, an adjustable stop adapted to be fixed in a plurality of predetermined positions, means on said shaft to cooperate with said stop to limit the rotation of said shaft, a switch operating member mounted eccentric to said shaft and rotatable therewith, a cover having an aperture therein, a toggle switch unit to be substituted for a removable cover plate having an operating arm adapted to extend through the aperture in said cover to be engaged by said operating member, and means removably to mount said switch unit on said cover.

4. In a replacement volume control adapted to replace any one of a plurality of types of volume controls the combination comprising a base, a resistance element supported thereon, a rotatable shaft mounted on said base carrying a contact means on said shaft to cooperate with said projection and said stop as desired to limit the rotation of said shaft, an index pin carried by said plate adapted to seat in any one oil a plurality of indexed pin engaging means to cooperate with plate securing means to hold said plate in a chosen indexed position whereby the desired amount of said fixed resistance section to be permanently connected in circuit may be obtained, a switch operating pin mounted eccentric to said shaft on an arm fixed to the latter, a cover having an aperture, an elongated slot and at least one lug hole therein, and a toggle switchunit to be substituted for a removable cover 'platehaving an operating arm to extend through the aperture in said, cover to be engaged by said operating pin, a resilient tongue and at least one lug, said tongue being adapted to project through said slot and engage the inner surface of said cover to hold said switch unit thereon when the latter is moved laterally oi the former until said lug snaps into the lug hole.

ARTHUR. HALL. 

